Concern over the safe use and disposal of reprographic chemicals used and generated in diazo-based reproduction facilities has increased greatly over the past decade. It is contemplated that strict environmental regulations for worker protection and disposal of reprographic chemicals and by-products will be promulgated in the very near future. As a result, creative methods and approaches for dealing with this problem are needed. Indeed, unless ways are developed to make these reproduction formats less environmentally damaging, it is probable that their use will be prohibited in the near future or greatly curtailed at a minimum.
Current chemical use in the diazo industry is based on a once-through approach for ammonia supply and emissions filtering. The ammonia, supplied as a gas (anhydrous) or liquid (aqueous), is utilized in the process to develop the print. Subsequently, a phosphoric acid filter is used to scrub the machine emissions to reduce ammonia vapors in the workplace environment. Unfortunately, the phosphoric acid filter media loses its effectiveness after it has been in use awhile and must be disposed of. The spent filter media contains a high concentration of ammonia, specifically ammonium phosphate, which is generally considered to be hazardous, even though ammonia is a natural constituent of the environment and often touted as being nondamaging environmentally. The problem is that in high concentrations, ammonia containing materials can adversely affect ground water and surface water systems.
Accordingly, it would be desirable if an environmentally safe way of disposing of the spent ammonia containing filter media were available. In the alternative, it would be desirable if the spent filter by-product could be recycled or used in some way so that it would not have to be disposed of in landfills, waste water treatment plants, or in other conventional treatment facilities.